The Obama administration has ambitions for a radical change in U.S. environmental policy. But President-elect Barack Obama did not pick radicals to lead it.

Instead, the three officials tapped for leadership posts on the environment are not activists but regulators who have spent years in the weeds of such issues as mercury emissions, brownfields and black-bear hunts.

They will inherit the usual issues -- dirty air, dirty water, brownfields and red tides -- plus an unprecedented one. Obama has promised to cut back U.S. emissions of greenhouse gases -- a proposal that could set off an enormous political fight.

A review of their records and past statements reveals little about the exact policies they would pursue under Obama. It shows they have won over some environmental activists with an open attitude and disappointed others who felt they were not pushing hard enough.

Their expected efforts to limit greenhouse gases would be more ambitious than changes they have sought in previous positions.

"It's going to be an enormous challenge," said Felicia Marcus, the western director for the Natural Resources Defense Council. "To call it 'herding cats' would be to oversimplify it. It's like herding dogs, cats, wolves and sheep."

Democratic sources say Obama plans to name Carol M. Browner, a former administrator of the Environmental Protection Agency, to a new position overseeing energy, environment and climate change policy from the White House. He will choose Lisa P. Jackson, who headed the New Jersey environment agency, as head of the EPA.

And, sources said, he will name Nancy Sutley, a deputy mayor in Los Angeles, to chair the White House Council on Environmental Quality. The president-elect is expected to announce the appointments next week.

Along with Steven Chu -- a Nobel Prize-winning physicist who sources say will be named secretary of energy -- the three will form the core of Obama's environmental team.

Word of their appointment was greeted enthusiastically yesterday by some environmental groups. The League of Conservation Voters called the group a "green dream team."

Industry groups were more cautious. At the U.S. Chamber of Commerce, Vice President William Kovacs said the group worried that the new officials would use their power to limit greenhouse-gas emissions and impose painful new costs on energy use.

"I think that they could be aggressive, and we're hoping that they're really going to look at the circumstances" of the economic downturn, Kovacs said. "That is our biggest single concern, because literally all three of them have a regulatory bent."

Victor Flatt, a law professor at the University of Houston who has studied environmental legislation, said he saw a strategy behind the picks. In a legislative fight about the right way to cut emissions, he said, it would be valuable to have officials who've been in similar state-level battles.

"This shows a really good understanding of the negotiations that are going to go on," Flatt said. He said that Sutley and Chu, who heads the Lawrence Berkeley National Laboratory in California, could bring valuable experience from that state. "California's just ahead of everybody else" on climate issues, he said.

Yesterday, Rep. Henry A. Waxman, who will be the new chairman of the House Committee on Energy and Commerce, called Obama's picks "outstanding people."

"It's going to be a dramatic change from what we've seen in the last eight years from the Bush administration, where even some of the agencies that were supposed to be working to protect the environment were doing all they could to undermine it," Waxman said in an interview.

Among the three tapped to be environmental officials, Browner is the best-known. During her eight years at EPA under President Bill Clinton, she led the fight for tougher air pollution standards, which the agency eventually won after a legal fight that led to the U.S. Supreme Court.

Two years ago, Browner was part of a group of former EPA leaders that called on the Bush administration to impose caps on greenhouse gases. Now, she will probably be called on to help Obama do that. The president-elect says he wants to reduce emissions to 1990 levels over 12 years.

Ed Krenik, who worked as the EPA's liaison to Congress for two years under Bush, said he worried that Browner's new role could upset government scientists if it is seen as a deadening layer of bureaucracy.

"If there's a concern out there, it's probably concern amongst EPA staff" that their director would have a less direct line to Obama, Krenik said. Browner declined a request to comment.

Jackson, who led the New Jersey environmental agency from 2006 to 2008, has impressed both activists and business groups with her open leadership style. An official at the New Jersey State Chamber of Commerce recalled that Browner agreed to give businesses in Paterson, N.J., a brush-up on environmental laws before sending officials in on an enforcement sweep. The leader of Environment New Jersey remembered calling Jackson on her cellphone to warn that legislation was being introduced to try to weaken environmental laws.

Jeff Ruch, executive director of Public Employees for Environmental Responsibility, said employees of the agency complained that Jackson was not tough enough in pushing for cleanups of polluted "brownfields," or requiring polluters to limit greenhouse gases.

"We called her a pliant technocrat, who sort of time after time did the wrong thing, but did it charmingly," he said.

But environmentalists credit her with stopping New Jersey's controversial bear hunt and urging Gov. Jon Corzine (D) to adopt an aggressive goal on climate change. The state committed to reducing emissions 20 percent by 2020 and 80 percent by 2050.

"I think she pushed [Corzine] as far as she could," said Dena Mottola Jaborska, executive director of Environment New Jersey. Still, New Jersey has found it difficult to say how it will reach those goals. A spokeswoman for the New Jersey Department of Environmental Protection said a climate action plan is overdue but expected next week.

Jackson declined to comment yesterday.

Sutley, tapped to lead the council on environmental quality, had worked for California Gov. Gray Davis (D). Marcus, of the Natural Resources Defense Council, supervised Sutley in the 1990s when she was a senior policy advisor at the EPA. Marcus described her as a quick study, easily able to master the technical details of any controversy.

"She's one of those people [to whom] you give the toughest issues," Marcus said. The Obama transition team did not respond to a request to interview Sutley.